Apex domains cannot have CNAME records.
Question and response
Question
dig wonder.net.tw. NS
Answer
wonder.net.tw. 5 NS ns1.wonder.net.tw.
wonder.net.tw. 5 NS ns2.wonder.net.tw.
Authority
The response has no authority records.
Additional
ns1.wonder.net.tw. 5 A 210.209.1.1
ns2.wonder.net.tw. 5 A 210.209.1.2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0